1. Field of the Invention
The present invention relates to a plurality of types of conveyor chain units (hereinafter simply referred to as the chain units) and a conveyor chain constructed of the plurality of types of the chain units, wherein the plurality of types of chain units are connected widthwise to form the conveyor chain which may vary in width of its conveying surface, depending upon the number and the types of the chain units used therein. More particularly, the present invention relates to two types of the chain units and a conveyor chain constructed of these two types of the chain units.
2. Description of the Prior Art
It is well known to form a conveyor chain by connecting widthwise a plurality of types of chain units which are generally made of plastic, wherein the conveyer chain may vary in width, depending on the number and the types of the chain units used therein.
In case of a conventional conveyor chain such as on described above, a chain unit used in each of opposite sides of the conveyor chain serves as a side member of the conveyor chain, and must receive a plug which is engaged with a connecting rod or pin for connecting adjacent chain units with each other. Consequently, the chain units used in the opposite side of the conveyor chain are different in type from those (i.e., intermediate chain units) used in an intermediate portion of the conveyor chain. Namely, in the conventional conveyor chain, at least two different types of the chain units are required. Consequently, when two types of the chain units, which are different in width to form a first and a second chain unit, are required in use, it is necessary to prepare at least four different types of the chain units, two of which are for the first chain unit to serve as a side member and an intermediate member of the conveyor chain constructed of the first chain unit, and the remaining two are for the second chain unit and serve as a side member and an intermediate member of the conveyor chain constructed of the second chain unit.
On the other hand, when the conveyor chain is constructed of two types of chain units one of which serves as a side member of the conveyor chain and the other serves as an intermediate member of the conveyor chain, adjacent side members of the conveyor chain are considerably separated widthwise from each other and have their pins exposed to the outside. These are disadvantages inherent in the conventional conveyor chain. Further, in the conventional conveyor chain, a plurality of chain units are connected widthwise to form a wide conveyor chain, which imposes a heavy load on a power train of the conveyor chain, so that a powerful motor is required. Due to such heavy load, it is also necessary for the conventional conveyor chain to increase its rigidity and has each of their chain units increased in thickness in construction.
As described above, it is necessary for the conventional wide conveyor chain to prepare a large number of its components, which increases tooling cost and stock control cost of the conveyor chain. Further, the assembling operations of the conventional conveyor chain take too much time and labor, which increases the manufacturing cost thereof.